What Kind of Bug Is This? Common Bug Groups

Is It a Cockroach? How to Tell Cockroaches From Look-Alikes

Cockroaches: 6 marks to check, what they are often confused with, whether they bite or sting, and where they turn up, quoted from university entomology and IPM sources.

These pages help you narrow a bug down to its group from what you can see. They are not medical advice. Seek medical care promptly for severe symptoms or any sign of an allergic reaction.

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At a glance

Group: Order Blattodea (superorder Dictyoptera)
Body plan: Cockroaches are broad, flattened insects with long antennae and a prominent shield-shaped section behind the head (the pronotum); adults have membranous wings (not the hardened forewings beetles have), and body size ranges from under 1/2 inch to almost 2 inches.
Size: Cockroaches range in size from less than 1/2 inch to almost 2 inches long. Examples: German cockroach 1/2-5/8 inch; Oriental cockroach about 1 inch; American cockroach up to about 1 1/2-2 inches; Pennsylvania wood cockroach up to 1 inch (males) / 3/4 inch (females).
Bites or stings: Sources do not describe cockroaches biting or stinging humans; they do describe cockroach excrement and cast skins as containing allergens that commonly cause allergic reactions.
Where you find them: Cockroaches hide by day in warm, dark, moist areas such as cracks, water meter boxes, sewers, and crawl spaces, coming out at night to feed; the German cockroach is the most common indoor species, especially in multi-unit housing.

How to tell it is one of the cockroaches

German cockroach: identified by small size plus two dark parallel lines running from the back of the head to the wings.
Oriental cockroach: adults are very dark brown to nearly black with a somewhat greasy body sheen.
Wood cockroaches are smaller/lighter than American cockroaches (which are larger, reddish-brown) and lighter-colored than Oriental cockroaches (dark brown to nearly black).
Cockroaches are sometimes confused with beetles, but cockroaches have membranous wings and lack beetles' thick, hardened forewings.
Termites are taxonomically close to cockroaches (both classified under Dictyoptera), which is why the two are sometimes conflated.
Pennsylvania wood cockroaches are not pests outdoors — they are ecosystem indicators/decomposers, unlike household pest species.

Often confused with

People most often mix cockroaches up with:

Open the other page and compare its list against the marks above; the differences are usually in the antennae, wings or the way the body is divided.

Bites and stings

Sources do not describe cockroaches biting or stinging humans; they do describe cockroach excrement and cast skins as containing allergens that commonly cause allergic reactions. Seek medical care promptly for severe symptoms or any allergic reaction.

Pest or beneficial?

Cockroaches are described as among the most important household and public-health pests, given their disease-transmission and allergen risks.

Where they turn up

Cockroaches hide by day in warm, dark, moist areas such as cracks, water meter boxes, sewers, and crawl spaces, coming out at night to feed; the German cockroach is the most common indoor species, especially in multi-unit housing.

How to photograph it for identification

Get as close as your camera will focus, from directly above, in daylight or a bright lamp. Include the whole body with the legs and antennae in frame; a second shot from the side shows wings and body segments. Put a coin or ruler next to it for scale. For a bite or a bug found on skin or bedding, photograph the bug itself, not the mark. The app names the likely group; use the list above to confirm.

FAQ

Do cockroaches bite or sting?

What is the quickest way to recognize cockroaches?

German cockroach: identified by small size plus two dark parallel lines running from the back of the head to the wings.

Are cockroaches a pest?

Cockroaches are described as among the most important household and public-health pests, given their disease-transmission and allergen risks.

How do I tell cockroaches from termites?

Cockroaches are sometimes confused with beetles, but cockroaches have membranous wings and lack beetles' thick, hardened forewings. Pennsylvania wood cockroaches are not pests outdoors — they are ecosystem indicators/decomposers, unlike household pest species. The Termites page lists its own marks.

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